Epstein-Barr virus in gastric carcinomas and gastric stump carcinomas: a late event in gastric carcinogenesis

RE.GA.IN.: the Real-world Gastritis Initiative-updating the updates

At the end of the last century, a far-sighted 'working party' held in Sydney, Australia addressed the clinicopathological issues related to gastric inflammatory diseases. A few years later, an international conference held in Houston, Texas, USA critically updated the seminal Sydney classification. In line with these initiatives, Kyoto Global Consensus Report, flanked by the Maastricht-Florence conferences, added new clinical evidence to the gastritis clinicopathological puzzle.The most relevant topics related to the gastric inflammatory diseases have been addressed by the Real-world Gastritis Initiative (RE.GA.IN.), from disease definitions to the clinical diagnosis and prognosis. This paper reports the conclusions of the RE.GA.IN. consensus process, which culminated in Venice in November 2022 after more than 8 months of intense global scientific deliberations. A forum of gastritis scholars from five continents participated in the multidisciplinary RE.GA.IN. consensus. After lively debates on the most controversial aspects of the gastritis spectrum, the RE.GA.IN. Faculty amalgamated complementary knowledge to distil patient-centred, evidence-based statements to assist health professionals in their real-world clinical practice. The sections of this report focus on: the epidemiology of gastritis; Helicobacter pylori as dominant aetiology of environmental gastritis and as the most important determinant of the gastric oncogenetic field; the evolving knowledge on gastric autoimmunity; the clinicopathological relevance of gastric microbiota; the new diagnostic horizons of endoscopy; and the clinical priority of histologically reporting gastritis in terms of staging. The ultimate goal of RE.GA.IN. was and remains the promotion of further improvement in the clinical management of patients with gastritis.

Clinical and pathologic characteristics of gastric adenocarcinoma associated with Epstein-Barr virus in a region with a high incidence of gastric cancer in Colombia

INTRODUCTION AND AIMS

Epstein-Barr virus (EBV) infection is an etiologic factor in EBV-associated gastric carcinoma (EBVaGC). The aim of our study was to describe the clinical and histopathologic characteristics of EBV infection in intestinal-type gastric adenocarcinoma samples.

MATERIAL AND METHODS

Of 180 paraffin-embedded gastrectomy samples, 28 were studied. Chromogenic in situ hybridization was performed to detect EBV. Sociodemographic and histopathologic data were obtained from the patients' clinical histories.

RESULTS

A total of 21.4% of the samples were positive for EBV. The predominant morphologic characteristic was the lace pattern, with dense inflammatory infiltration. Fifty percent of the EBVaGC+ patients were men, and the median age of the positive patients was 59 years (range: 50-75); 77.2% of the EBVaGC- patients were men, and the median age of the negative patients was 66 years (range: 34-89). Helicobacter pylori infection was associated with 10.7% of the EBVaGC+ patients and 53.6% of the EBVaGC- patients. In the EBVaGC+ patients, the cardia was the most frequent tumor location (17.9%), 7.1% had histologic grades 2 and 3, and 17.9% presented with Borrmann classification type III. In the EBVaGC- patients, the cardia and fundus were the most frequent tumor locations (71.4%), 35.7% had histologic grade 2, and 39.3% and 21.4% presented with Borrmann classification type III and IV, respectively.

CONCLUSIONS

The present study describes the clinical and histopathologic characteristics associated with EBVaGC positivity. Those data may aid in the selection of cases that are candidates for analysis through molecular methods aimed at identifying EBV infection in intestinal-type gastric adenocarcinoma.

Updates on Epstein-Barr Virus (EBV)-Associated Nasopharyngeal Carcinoma: Emphasis on the Latent Gene Products of EBV

Nasopharyngeal carcinoma (NPC) is an uncommon type of malignancy/cancer worldwide. However, NPC is an endemic disease in southeast Asia and southern China and the reasons behind the underlying for such changes are unclear. Even though the Epstein-Barr infection (EBV) has been suggested as an important reason for undistinguishable NPC, the EBV itself is not adequate to source this type of cancer. The risk factors, for example, genetic susceptibility, and environmental factors might be associated with EBV to undertake a part in the NPC carcinogenesis. Normal healthy people have a memory B cell pool where the EBV persists, and any disturbance of this connection leads to virus-associated B cell malignancies. Less is known about the relationship between EBV and epithelial cell tumors, especially the EBV-associated nasopharyngeal carcinoma (EBVaNPC) and EBV-associated gastric carcinoma (EBVaGC). Currently, it is believed that premalignant genetic changes in epithelial cells contribute to the aberrant establishment of viral latency in these tumors. The early and late phases of NPC patients' survival rates vary significantly. The presence of EBV in all tumor cells presents prospects for the development of innovative therapeutic and diagnostic techniques, despite the fact that the virus's exact involvement in the carcinogenic process is presently not very well known. EBV research continues to shed light on the carcinogenic process, which is important for a more comprehensive knowledge of tumor etiology and the development of targeted cancer therapeutics. In order to screen for NPC, EBV-related biomarkers have been widely used in a few high-incidence locations because of their close associations with the risks of NPC. The current review highlights the scientific importance of EBV and its possible association with NPC.

Development of Epstein-Barr virus-associated gastric cancer: Infection, inflammation, and oncogenesis

Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) cells originate from a single-cell clone infected with EBV. However, more than 95% of patients with gastric cancer have a history of Helicobacter pylori (H. pylori) infection, and H. pylori is a major causative agent of gastric cancer. Therefore, it has long been argued that H. pylori infection may affect the development of EBVaGC, a subtype of gastric cancer. Atrophic gastrointestinal inflammation, a symptom of H. pylori infection, is observed in the gastric mucosa of EBVaGC. Therefore, it remains unclear whether H. pylori infection is a cofactor for gastric carcinogenesis caused by EBV infection or whether H. pylori and EBV infections act independently on gastric cancer formation. It has been reported that EBV infection assists in the onco-genesis of gastric cancer caused by H. pylori infection. In contrast, several studies have reported that H. pylori infection accelerates tumorigenesis initiated by EBV infection. By reviewing both clinical epidemiological and experimental data, we reorganized the role of H. pylori and EBV infections in gastric cancer formation.

Molecular subtyping of gastroesophageal dysplasia heterogeneity according to TCGA/ACRG classes

Gastric adenocarcinoma has recently been classified into several subtypes on the basis of molecular profiling, which has been successfully reproduced by immunohistochemistry (IHC) and in situ hybridization (ISH). A series of 73 gastroesophageal dysplastic lesions (37 gastric dysplasia and 36 Barrett dysplasia; 44 low-grade dysplasia and 29 high-grade dysplasia) was investigated for mismatch repair proteins, E-cadherin, p53, and EBER status, to reproduce The Cancer Genome Atlas (TCGA) and Asian Cancer Research Group (ACRG) molecular clustering. Overall, the dysplastic lesions were classified as follows: according to TCGA classification, EBV, 0/73 (0%), MSI, 6/73 (8.2%), GS, 4/73 (5.5%), CIN, 63/73 (86.3%); according to ACRG molecular subtyping, MSI, 6/73 (8.2%), MSS/EMT, 4/73 (5.5%), MSS/TP53⁻, 33/73 (45.2%), MSS/TP53⁺, 30/73 (41.1%). A positive association was found between MSS/TP53⁻ and Barrett dysplasia (p = 0.0004), between MSS/TP53⁺ and LG dysplasia (p = 0.001) and between MSS/TP53⁺ and gastric dysplasia (p = 0.0018). Gastroesophageal dysplastic lesions proved to be heterogenous in terms of TCGA/ACRG classes, but with a different distribution from that of cancers, with no EBV-positive cases, an increasing presence of mismatch repair deficiency from low grade to high grade lesions, and a prevalence of p53 aberrations in Barrett dysplasia. The present study further demonstrated that gastroesophageal dysplastic lesions may be characterized by alterations in predictive/prognostic biomarkers, and this should be considered in routine diagnostic.

Epstein-Barr Virus-Associated Gastric Cancer: Old Entity with New Relevance

Gastric cancer (GC) represents a major public health issue worldwide, being the fifth most common cancer and one of the leading causes of death by cancer. In 2014, The Cancer Genome Atlas (TCGA) established that tumors positive for Epstein-Barr virus (EBV) are considered a specific subtype of GC (EBVaGC). Several meta-analyses have shown that EBVaGC represents almost 10% of all gastric cancer worldwide, with small differences in the geographic distribution. This tumor subtype has a high potential of being clinically relevant and studies have shown that it has specific features, a better prognosis, and increased overall survival. In this review, we summarize some of the most frequent aspects of EBVaGC, including the specific features of this GC subtype, data regarding the potential steps of EBVaGC carcinogenesis, and perspectives on treatment opportunities.

Clinicopathological Features of Remnant Gastric Cancer After Gastrectomy

BACKGROUND

Remnant gastric cancer (RGC) encompasses all cancers arising from the remnant stomach. Various studies have reported on RGC and its prognosis, but no consensus on its surgical treatment and postoperative management has been reached. Moreover, the correlation between the clinicopathological characteristics and long-term outcomes of RGC remains unclear. This study investigated the clinicopathological factors associated with the long-term survival of RGC patients.

METHODS

The medical records (March 1993-September 2020) of 104 RGC patients from Tokyo Medical University Hospital database were analyzed. Of these 104 patients, the medical records of 63 patients who underwent surgical curative resection were analyzed using R. Kaplan-Meier plots of cumulative incidence of RGC were made. Differences in survival rates were compared using the log-rank test. Prognostic factors were analyzed using multivariate Cox regression analysis (P < .05).

RESULTS

Of the 104 RGC patients, 63 underwent total remnant stomach excision. The median time from the first surgery to the total excision was 10 years. The 5-year survival rate of the 63 RGC patients was .55 ((95% CI); .417-.671). The clinicopathological factors that were significantly associated with the long-term outcome of the RGC patients were tumor diameter (≥3.5 cm), presence or absence of combined resection of multiple organs, tumor invasion (deeper than T2), TNM stage, and postoperative morbidity. The multivariate Cox regression analysis showed that tumor invasion depth was the only independent prognostic factor for RGC patients [HR (95% CI): 5.49 (2.629-11.5), P ≤ .005].

CONCLUSIONS

Among prognostic factors, tumor invasion depth was the only independent factor affecting RGC's long-term outcome.

Epstein-Barr virus associated gastric dysplasia: a new rare entity?

Epstein-Barr virus (EBV) infection characterizes a portion of gastric adenocarcinomas. However, since there is lack of evidence of EBV presence in pre-neoplastic lesions of gastric mucosa, the etiologic role of EBV in gastric carcinogenesis is still debated. We report an unusual case of an EBV-associated foveolar gastric dysplasia associated with a focus of EBV-positive low-grade tubular adenocarcinoma, arisen in the context of a lymphocytic-like (EBV-positive) gastritis. The present case offers the unique opportunity to determine whether EBV is an early or late event in gastric cancer development and to evaluate its prevalence in patients with gastric dysplasia. To properly address this question, we investigated EBER expression in a large mono-institutional series of gastric and gastro-esophageal cancers (n = 594) and associated precursor lesions (n = 84). All the selected gastric dysplastic lesions (n = 43) resulted EBV negative. In most cases, EBV is present only in gastric and gastroesophageal junction adenocarcinomas, but not in their precursor lesions. However, the reported case indicates that non-conventional EBV-associated dysplasia may represent a novel histopathological entity in the gastric dysplasia scenario and that EBV could play an early direct role in gastric carcinogenesis.

Overview of Epstein-Barr-Virus-Associated Gastric Cancer Correlated with Prognostic Classification and Development of Therapeutic Options

Gastric cancer (GC) is a deadly disease with poor prognosis that is characterized by heterogeneity. New classifications based on histologic features, genotypes, and molecular phenotypes, for example, the Cancer Genome Atlas subtypes and those by the Asian Cancer Research Group, help understand the carcinogenic differences in GC and have led to the identification of an Epstein–Barr virus (EBV)-related GC subtype (EBVaGC), providing new indications for tailored treatment and prognostic factors. This article provides a review of the features of EBVaGC and an update on the latest insights from EBV-related research with a particular focus on the strict interaction between EBV infection and the gastric tumor environment, including the host immune response. This information may help increase our knowledge of EBVaGC pathogenesis and the mechanisms that sustain the immune response of patients since this mechanism has been demonstrated to offer a survival advantage in a proportion of patients with GC.

From Interconnection between Genes and Microenvironment to Novel Immunotherapeutic Approaches in Upper Gastro-Intestinal Cancers-A Multidisciplinary Perspective

Despite the progress during the last decade, patients with advanced gastric and esophageal cancers still have poor prognosis. Finding optimal therapeutic strategies represents an unmet need in this field. Several prognostic and predictive factors have been evaluated and may guide clinicians in choosing a tailored treatment. Data from large studies investigating the role of immunotherapy in gastrointestinal cancers are promising but further investigations are necessary to better select those patients who can mostly benefit from these novel therapies. This review will focus on the treatment of metastatic esophageal and gastric cancer. We will review the standard of care and the role of novel therapies such as immunotherapies and CAR-T. Moreover, we will focus on the analysis of potential predictive biomarkers such as Modify as: Microsatellite Instability (MSI) and PD-L1, which may lead to treatment personalization and improved treatment outcomes. A multidisciplinary point of view is mandatory to generate an integrated approach to properly exploit these novel antiproliferative agents.

The importance of Epstein-Barr virus infection in the systemic treatment of patients with gastric cancer

The Epstein-Barr virus (EBV) may directly cause the development of EBV-associated gastric cancer (EBVaGC). The prevalence of EBVaGC ranges from 4% to 18%, with a 2-fold higher frequency in males, and in tumors arising in the gastric cardia or corpus and 4 times higher frequency in gastric stump carcinoma. The vast majority of EBVaGC are lymphoepithelioma-like carcinomas. Despite extensive nodal involvement and distant metastases at initial diagnosis, EBVaGC seems to be a distinct etiologic entity with a favorable prognosis. However, the lymphoepithelioma-like carcinomas subtype in EBVaGC cannot be recognized in the current molecular classifications. Neither is there an association between EBV positivity and survival of patients after curative gastrectomy if they received standard adjuvant chemotherapy, nor EBV positivity and prediction of response to neoadjuvant platinum/5-FU-based chemotherapy. Alterations in chemokines and PD-L1 provide theoretical justification for clinical evaluation of immune checkpoint therapy in EBVaGC. Moreover, a higher degree of host immune response was demonstrated in EBVaGC. The current histologic and molecular GC classification does not influence clinical practice. Further research is expected to find convenient methods to assess gastric subtypes in day-to-day practice and to tailor therapy to improve overall survival.

Circulating Antibodies against Epstein-Barr Virus (EBV) and p53 in EBV-Positive and -Negative Gastric Cancer

BACKGROUND

Epstein-Barr virus (EBV)-positive gastric cancers have clinicopathologic differences from EBV-negative tumors and lack TP53 mutation. Serologic profiles may inform viral contribution to carcinogenesis.

METHODS

We compared humoral responses of EBV-positive (n = 67) and EBV-negative (n = 137) patients with gastric cancer from the International EBV-Gastric Cancer Consortium. Serum antibodies against four EBV proteins, nuclear (EBNA), viral capsid (VCA), early-diffuse (EA-D), and Zta replication activator (ZEBRA), and to p53 were assessed by multiplex assays. OR of antibody level tertiles (T1-T3) were adjusted by logistic regression. We also conducted a meta-analysis of reported anti-p53 seropositivity in gastric cancer.

RESULTS

Consistent with EBV's ubiquity, 99% of patients were seropositive for anti-EBNA and 98% for anti-VCA, without difference by tumor EBV status. Seropositivity varied between patients with EBV-positive and EBV-negative tumors for anti-EA-D (97% vs. 67%, respectively, P < 0.001) and anti-ZEBRA (97% vs. 85%, respectively, P = 0.009). Adjusted ORs (vs. T1) for patients with EBV-positive versus EBV-negative tumors were significantly elevated for higher antibodies against EBNA (2.6 for T2 and 13 for T3), VCA (1.8 for T2 and 2.4 for T3), EA-D (6.0 for T2 and 44 for T3), and ZEBRA (4.6 for T2 and 12 for T3). Antibodies to p53 were inversely associated with EBV positivity (3% vs. 15%; adjusted OR = 0.16, P = 0.021). Anti-p53 prevalence from the literature was 15%.

CONCLUSIONS

These serologic patterns suggest viral reactivation in EBV-positive cancers and identify variation of p53 seropositivity by subtype.

IMPACT

Anti-EBV and anti-p53 antibodies are differentially associated with tumor EBV positivity. Serology may identify EBV-positive gastric cancer for targeted therapies.

An evaluation of HHV-6 as an etiologic agent in Hodgkin lymphoma and brain cancer using IARC criteria for oncogenicity

BACKGROUND

Human herpesvirus-6 (HHV-6) is a ubiquitous double-stranded DNA virus that can cause roseola infantum, encephalitis, and seizure disorders. Several studies have shown an association between HHV-6 and cancer but confirmation of an etiologic role is lacking. We reviewed the criteria for viral causation of cancer used by The International Agency for Research on Cancer (IARC) for six oncogenic viruses and applied criteria to published reports of HHV-6 and its association with Hodgkin lymphoma and brain tumors.

METHODS

Our major criteria for oncogenicity were finding evidence of the virus in every tumor cell and prevention of the tumor by an antiviral vaccine. Our six minor criteria included: 1) suggestive serologic correlation, such as higher virus antibody levels in cases compared to controls; 2) evidence of the virus in some but not all tumor cells, and 3) time space clustering. We focused on Epstein-Barr virus (EBV) as the primary virus for comparison as HHV-6 and EBV are both Herpesviridae, ubiquitous infections, and EBV is well-accepted as a human oncovirus. Particular attention was given to Hodgkin lymphoma (HL) and brain cancer as these malignancies have been the most studied.

RESULTS

No studies reported HHV-6 satisfying either of the major criteria for oncogenicity. Of the minor criteria used by IARC, serologic studies have been paramount in supporting EBV as an oncogenic agent in all EBV-associated tumors, but not for HHV-6 in HL or brain cancer. Clustering of cases was suggestive for both HL and brain cancer and medical intervention suggested by longer survival in patients treated with antiviral agents was reported for brain cancer.

CONCLUSION

There is insufficient evidence to indicate HHV-6 is an etiologic agent with respect to HL and brain cancers. We suggest that methods demonstrating EBV oncogenicity be applied to HHV-6. It is important that one study has found HHV-6 in all cancer cells in oral cancer in a region with elevated HHV-6 antibodies and therefore HHV-6 can still be considered a possible human oncogenic virus.

Epstein-Barr virus is absent in gastric superficial neoplastic lesions

Epstein-Barr virus (EBV) has been associated with about 9% of all gastric carcinomas, but its role in gastric carcinogenesis remains unclear since there is lack of evidence of EBV presence in pre-neoplastic lesions of gastric mucosa. This study intends to determine the prevalence of EBV in gastric dysplasia and superficial neoplasia to clarify whether EBV infection is an early or late event in gastric cancer development. This retrospective study included a total of 242 gastric lesions from 199 consecutive patients who were referred for endoscopic resection. The histological classification of lesions includes 137 low- and high-grade dysplasia and 105 superficial carcinomas. EBV infection was investigated by EBER-ISH. Results showed that EBV was not detected in any epithelial cells of any case with dysplasia or superficial carcinomas, although we observed the presence of a small number of EBV-infected lymphocytes in 2.1% of all lesions. These results showed that EBV is not present in gastric dysplasia neither in superficial carcinomas suggesting that EBV carcinogenesis is a late event in well/moderately differentiated gastric carcinogenesis.

Carcinoma in the Remnant Stomach During Long-Term Follow-up After Distal Gastrectomy for Gastric Cancer: Analysis of Cumulative Incidence and Associated Risk Factors

BACKGROUND

The number of patients with remnant gastric cancer following resection of gastric cancer may increase. The aims of this study were to investigate the development of remnant gastric cancer after distal gastrectomy for gastric cancer and to examine its cumulative incidence, clinicopathological characteristics, and risk factors.

METHODS

We examined 437 patients with relapse-free survival for 5 years or more after distal gastrectomy with Billroth I reconstruction for gastric cancer performed between 1985 and 2005.

RESULTS

A total of 17 patients suffered from remnant gastric cancer. The cumulative incidence was 3.7% at 10 years and 5.4% at 20 years. The median time until development of remnant gastric cancer was 79 months (range 30-209 months). The presence of synchronous multiple gastric cancers was a significant independent risk factor for remnant gastric cancer (hazard ratio 4.036; 95% confidence interval 1.478-11.02; P = 0.006). Of the 17 patients, the 13 whose remnant gastric cancer was detected via regular endoscopy showed better prognoses than the patients detected by other means (P < 0.001).

CONCLUSION

The cumulative incidence of remnant gastric cancer was 5.4% at 20 years. In particular, patients who had multiple gastric cancers at initial gastrectomy were at higher risk for remnant gastric cancer. Therefore, long-term endoscopic surveillance is important.

The Pattern of Signatures in Gastric Cancer Prognosis

Gastric cancer is one of the most common malignancies worldwide and it is a fourth leading cause of cancer-related death. Carcinogenesis is a multistage disease process specified by the gradual procurement of mutations and epigenetic alterations in the expression of different genes, which finally lead to the occurrence of a malignancy. These genes have diversified roles regarding cancer development. Intracellular pathways are assigned to the expression of different genes, signal transduction, cell-cycle supervision, genomic stability, DNA repair, and cell-fate destination, like apoptosis, senescence. Extracellular pathways embrace tumour invasion, metastasis, angiogenesis. Altered expression patterns, leading the different clinical responses. This review highlights the list of molecular biomarkers that can be used for prognostic purposes and provide information on the likely outcome of the cancer disease in an untreated individual.

Epstein-Barr virus and mismatch repair deficiency status differ between oesophageal and gastric cancer: A large multi-centre study

BACKGROUND

Oesophageal (OeC) and gastric (GC) cancer patients are treated with similar multimodal therapy and have poor survival. There remains an urgent clinical need to identify biomarkers to individualise patient management and improve outcomes. Therapy with immune checkpoint inhibitors has shown promising results in other cancers. Proposed biomarkers to predict potential response to immune checkpoint inhibitors include DNA mismatch repair (MMR) and/or Epstein-Barr virus (EBV) status. The aim of this study was to establish and compare EBV status and MMR status in large multi-centre series of OeC and GC.

METHODS

EBV was assessed by EBV-encoded RNA (EBER) in situ hybridisation and MMR protein expression by immunohistochemistry (IHC) in 988 OeC and 1213 GC from multiple centres. In a subset of OeC, microsatellite instability (MSI) was tested in parallel with MMR IHC.

RESULTS

Frequency of MMR deficiency (MMRdef) and MSI was low in OeC (0.8% and 0.6%, respectively) compared with GC (10.3%). None of the OeCs were EBER positive in contrast to 4.8% EBER positive GC. EBV positive GC patients were younger (p = 0.01), more often male (p = 0.001) and had a better overall survival (p = 0.012). MMRdef GC patients were older (p = 0.001) and showed more often intestinal-type histology (p = 0.022).

CONCLUSIONS

This is the largest study to date indicating that EBV and MMRdef do not play a role in OeC carcinogenesis in contrast to GC. The potential clinical usefulness of determining MMRdef/EBV status to screen patients for eligibility for immune-targeting therapy differs between OeC and GC patients.

Gastric cancer: epidemiology, prevention, classification, and treatment

Gastric cancer is the second most common cause of cancer-related deaths in the world, the epidemiology of which has changed within last decades. A trend of steady decline in gastric cancer incidence rates is the effect of the increased standards of hygiene, conscious nutrition, and Helicobacter pylori eradication, which together constitute primary prevention. Avoidance of gastric cancer remains a priority. However, patients with higher risk should be screened for early detection and chemoprevention. Surgical resection enhanced by standardized lymphadenectomy remains the gold standard in gastric cancer therapy. This review briefly summarizes the most important aspects of gastric cancers, which include epidemiology, risk factors, classification, diagnosis, prevention, and treatment. The paper is mostly addressed to physicians who are interested in updating the state of art concerning gastric carcinoma from easily accessible and credible source.

Immunotherapy against cancer-related viruses

Approximately 12% of all cancers worldwide are associated with viral infections. To date, eight viruses have been shown to contribute to the development of human cancers, including Epstein-Barr virus (EBV), Hepatitis B and C viruses, and Human papilloma virus, among others. These DNA and RNA viruses produce oncogenic effects through distinct mechanisms. First, viruses may induce sustained disorders of host cell growth and survival through the genes they express, or may induce DNA damage response in host cells, which in turn increases host genome instability. Second, they may induce chronic inflammation and secondary tissue damage favoring the development of oncogenic processes in host cells. Viruses like HIV can create a more permissive environment for cancer development through immune inhibition, but we will focus on the previous two mechanisms in this review. Unlike traditional cancer therapies that cannot distinguish infected cells from non-infected cells, immunotherapies are uniquely equipped to target virus-associated malignancies. The targeting and functioning mechanisms associated with the immune response can be exploited to prevent viral infections by vaccination, and can also be used to treat infection before cancer establishment. Successes in using the immune system to eradicate established malignancy by selective recognition of virus-associated tumor cells are currently being reported. For example, numerous clinical trials of adoptive transfer of ex vivo generated virus-specific T cells have shown benefit even for established tumors in patients with EBV-associated malignancies. Additional studies in other virus-associated tumors have also been initiated and in this review we describe the current status of immunotherapy for virus-associated malignancies and discuss future prospects.

Epstein-Barr virus: more than 50 years old and still providing surprises

It is more than 50 years since the Epstein-Barr virus (EBV), the first human tumour virus, was discovered. EBV has subsequently been found to be associated with a diverse range of tumours of both lymphoid and epithelial origin. Progress in the molecular analysis of EBV has revealed fundamental mechanisms of more general relevance to the oncogenic process. This Timeline article highlights key milestones in the 50-year history of EBV and discusses how this virus provides a paradigm for exploiting insights at the molecular level in the diagnosis, treatment and prevention of cancer.

Anti-Helicobacter pylori Antibody Profiles in Epstein-Barr virus (EBV)-Positive and EBV-Negative Gastric Cancer

BACKGROUND

Helicobacter pylori is the primary cause of gastric cancer, but about 9% of cases harbor Epstein-Barr virus (EBV) in the tumor cells. There is limited evidence on the possible interaction or antagonism between these infectious agents in gastric carcinogenesis.

METHODS

We compared H. pylori serologic profiles of EBV-positive (n = 58) and EBV-negative (n = 111) noncardia gastric cancer patients from the United States National Cancer Institute's International EBV-Gastric Cancer Consortium. EBV positivity of tumors was assessed by in situ hybridization. Serum levels of 15 antibodies to immunogenic proteins of H. pylori (Cad, CagA, Cagδ, CagM, Catalase, GroEL, HcpC, HP0231, HP0305, HpaA, HyuA, NapA, Omp, UreA, VacA) were assessed using bead-based multiplex serology. Logistic regression models were used to adjust odds ratios (OR) for country, age, sex, and year of diagnosis.

RESULTS

Seropositivity to individual proteins ranged up to 90% overall. Antibodies to Catalase were borderline associated with tumor EBV positivity (adjusted OR = 3.15, p = .0024, Bonferroni corrected p = .036). Distributions of other antibodies did not vary by tumor EBV status.

CONCLUSION

Similarity of host-response indicates the essential etiological role of H. pylori in EBV-positive gastric cancer.

Signatures of tumour immunity distinguish Asian and non-Asian gastric adenocarcinomas

OBJECTIVE

Differences in gastric cancer (GC) clinical outcomes between patients in Asian and non-Asian countries has been historically attributed to variability in clinical management. However, recent international Phase III trials suggest that even with standardised treatments, GC outcomes differ by geography. Here, we investigated gene expression differences between Asian and non-Asian GCs, and if these molecular differences might influence clinical outcome.

DESIGN

We compared gene expression profiles of 1016 GCs from six Asian and three non-Asian GC cohorts, using a two-stage meta-analysis design and a novel biostatistical method (RUV-4) to adjust for technical variation between cohorts. We further validated our findings by computerised immunohistochemical analysis on two independent tissue microarray (TMA) cohorts from Asian and non-Asian localities (n=665).

RESULTS

Gene signatures differentially expressed between Asians and non-Asian GCs were related to immune function and inflammation. Non-Asian GCs were significantly enriched in signatures related to T-cell biology, including CTLA-4 signalling. Similarly, in the TMA cohorts, non-Asian GCs showed significantly higher expression of T-cell markers (CD3, CD45R0, CD8) and lower expression of the immunosuppressive T-regulatory cell marker FOXP3 compared to Asian GCs (p<0.05). Inflammatory cell markers CD66b and CD68 also exhibited significant cohort differences (p<0.05). Exploratory analyses revealed a significant relationship between tumour immunity factors, geographic locality-specific prognosis, and postchemotherapy outcomes.

CONCLUSIONS

Analyses of >1600 GCs suggest that Asian and non-Asian GCs exhibit distinct tumour immunity signatures related to T-cell function. These differences may influence geographical differences in clinical outcome, and the design of future trials particularly in immuno-oncology.

Case–control study of Epstein–Barr virus and Helicobacter pylori serology in Latin American patients with gastric disease

Background:

Chronic tissue damage induced by Helicobacter pylori (HP)-driven inflammation is considered the main risk of gastric carcinoma (GC). Epstein–Barr virus (EBV) infection has also been associated with GC. In this study, we aim to address the role of EBV in inflammatory GC precursor lesions and its added risk to HP infection.

Methods:

Antibodies against EBV, HP and the bacterial virulence factor CagA were measured in sera from 525 Mexican and Paraguayan patients with gastric disease. Gastric samples were characterised according to the updated Sydney classification and associations were estimated between antibody responses and severity of both tissue damage and inflammation.

Results:

We found significant associations (odd ratios and trends) between EBV and HP copositivity and premalignant lesions and intestinal-type GC. The EBV and HP coinfection was also significantly associated with increased infiltration of immune cells. No association was found between EBV and the less inflammation-driven diffuse-type GC.

Conclusions:

Our study suggests that EBV co-participates with HP to induce severe inflammation, increasing the risk of progression to intestinal-type GC.

Profiles of Epstein-Barr virus associated gastric carcinomas in Brunei Darussalam

BACKGROUND

Gastric cancer is the second most common gastrointestinal cancer and is largely attributed to Helicobacter pylori (H. pylori) infection. In addition, studies have also shown association with Epstein-Barr virus (EBV) in 10% of gastric cancers. This study assessed the characteristics of EBV associated gastric cancers (EBVaGC) in Brunei Darussalam.

MATERIALS AND METHODS

This study included gastric cancers diagnosed between 2008 and 2012, registered with the Department of Pathology RIPAS Hospital, Brunei Darussalam. Clinical case notes were systematically reviewed. Histology specimens were all stained for EBV and also assessed for intestinal metaplasia and H. pylori.

RESULTS

There were a total of 81 patients (54 male and 27 females) with a mean age of 65.8±14.8 years included in the study. Intestinal metaplasia and active H. pylori infection were detected in 40.7% and 30.9% respectively. A majority of the tumors were proximally located (55.6%), most poorly differentiated (well differentiated 16%, moderately differentiated 30.9% and poorly differentiated 53.1%) and the stages at diagnosis were; stage I (44.4%), stage II (23.5%), stage III (8.6%) and stage IV (23.5%). EBV positivity (EBVaGC) was seen in 30.9%. Between EBVaGC and EBV negative gastric cancers, there were no significant differences (age, gender, ethnic group, presence of Intestinal metaplasia, tumor locations, stages of disease and degree of tumor differentiation).

CONCLUSIONS

This study showed that a third of gastric cancers in Brunei Darussalam were positive for EBV, higher than what have been reported in the literature. However, there were no significant differences between EBVaGC and EBV negative gastric cancers. This suggests that the role of EBV in gastric cancer may be mostly incidental rather than any causal relation. However, further studies are required.

Molecular classification of gastric adenocarcinoma: translating new insights from the cancer genome atlas research network

Gastric cancer is a heterogenous cancer, which may be classified into several distinct subtypes based on pathology and epidemiology, each with different initiating pathological processes and each possibly having different tumor biology. A classification of gastric cancer should be important to select patients who can benefit from the targeted therapies or to precisely predict prognosis. The Cancer Genome Atlas (TCGA) study collaborated with previous reports regarding subtyping gastric cancer but also proposed a refined classification based on molecular characteristics. The addition of the new molecular classification strategy to a current classical subtyping may be a promising option, particularly stratification by Epstein-Barr virus (EBV) and microsatellite instability (MSI) statuses. According to TCGA study, EBV gastric cancer patients may benefit the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) antibodies or phosphoinositide 3-kinase (PI3K) inhibitors which are now being developed. The discoveries of predictive biomarkers should improve patient care and individualized medicine in the management since the targeted therapies may have the potential to change the landscape of gastric cancer treatment, moreover leading to both better understanding of the heterogeneity and better outcomes. Patient enrichment by predictive biomarkers for new treatment strategies will be critical to improve clinical outcomes. Additionally, liquid biopsies will be able to enable us to monitor in real-time molecular escape mechanism, resulting in better treatment strategies.

Telomerase activity impacts on Epstein-Barr virus infection of AGS cells

The Epstein-Barr virus (EBV) is transmitted from host-to-host via saliva and is associated with epithelial malignancies including nasopharyngeal carcinoma (NPC) and some forms of gastric carcinoma (GC). Nevertheless, EBV does not transform epithelial cells in vitro where it is rapidly lost from infected primary epithelial cells or epithelial tumor cells. Long-term infection by EBV, however, can be established in hTERT-immortalized nasopharyngeal epithelial cells. Here, we hypothesized that increased telomerase activity in epithelial cells enhances their susceptibility to infection by EBV. Using HONE-1, AGS and HEK293 cells we generated epithelial model cell lines with increased or suppressed telomerase activity by stable ectopic expression of hTERT or of a catalytically inactive, dominant negative hTERT mutant. Infection experiments with recombinant prototypic EBV (rB95.8), recombinant NPC EBV (rM81) with increased epithelial cell tropism compared to B95.8, or recombinant B95.8 EBV with BZLF1-knockout that is not able to undergo lytic replication, revealed that infection frequencies positively correlate with telomerase activity in AGS cells but also partly depend on the cellular background. AGS cells with increased telomerase activity showed increased expression mainly of latent EBV genes, suggesting that increased telomerase activity directly acts on the EBV infection of epithelial cells by facilitating latent EBV gene expression early upon virus inoculation. Thus, our results indicate that infection of epithelial cells by EBV is a very selective process involving, among others, telomerase activity and cellular background to allow for optimized host-to-host transmission via saliva.

Reprint of: cancer "causation" by infections--individual contributions and synergistic networks

The search for infectious agents playing a role in human carcinogenesis and their identification remain important issues. This could provide clues for a broader spectrum of cancers preventable by vaccination and accessible to specific therapeutic regimens. Yet, the various ways of interacting among different factors functioning synergistically and their different modes of affecting individual cells should bring to question the validity of the term "causation". It also should put a word of caution into all attempts to summarize criteria for "causality" of infectious agents in cancer development. At least in the opinion of these authors, we would be much better off avoiding these terms, replacing "causal factor" by "risk factor" and grading them according to their contribution to an individual's cancer risk.

Genomic assays for Epstein-Barr virus-positive gastric adenocarcinoma

A small set of gastric adenocarcinomas (9%) harbor Epstein–Barr virus (EBV) DNA within malignant cells, and the virus is not an innocent bystander but rather is intimately linked to pathogenesis and tumor maintenance. Evidence comes from unique genomic features of host DNA, mRNA, microRNA and CpG methylation profiles as revealed by recent comprehensive genomic analysis by The Cancer Genome Atlas Network. Their data show that gastric cancer is not one disease but rather comprises four major classes: EBV-positive, microsatellite instability (MSI), genomically stable and chromosome instability. The EBV-positive class has even more marked CpG methylation than does the MSI class, and viral cancers have a unique pattern of methylation linked to the downregulation of CDKN2A (p16) but not MLH1. EBV-positive cancers often have mutated PIK3CA and ARID1A and an amplified 9p24.1 locus linked to overexpression of JAK2, CD274 (PD-L1) and PDCD1LG2 (PD-L2). Multiple noncoding viral RNAs are highly expressed. Patients who fail standard therapy may qualify for enrollment in clinical trials targeting cancer-related human gene pathways or promoting destruction of infected cells through lytic induction of EBV genes. Genomic tests such as the GastroGenus Gastric Cancer Classifier are available to identify actionable variants in formalin-fixed cancer tissue of affected patients.

Epstein-Barr Virus-Specific Humoral Immune Responses in Health and Disease

Epstein-Barr virus (EBV) is widely distributed in the world and associated with a still increasing number of acute, chronic, malignant and autoimmune disease syndromes. Humoral immune responses to EBV have been studied for diagnostic, pathogenic and protective (vaccine) purposes. These studies use a range of methodologies, from cell-based immunofluorescence testing to antibody-diversity analysis using immunoblot and epitope analysis using recombinant or synthetic peptide-scanning. First, the individual EBV antigen complexes (VCA , MA, EA(D), EA(R) and EBNA) are defined at cellular and molecular levels, providing a historic overview. The characteristic antibody responses to these complexes in health and disease are described, and differences are highlighted by clinical examples. Options for EBV vaccination are briefly addressed. For a selected number of immunodominant proteins, in particular EBNA1, the interaction with human antibodies is further detailed at the epitope level, revealing interesting insights for structure, function and immunological aspects, not considered previously. Humoral immune responses against EBV-encoded tumour antigens LMP1, LMP2 and BARF1 are addressed, which provide novel options for targeted immunotherapy. Finally, some considerations on EBV-linked autoimmune diseases are given, and mechanisms of antigen mimicry are briefly discussed. Further analysis of humoral immune responses against EBV in health and disease in carefully selected patient cohorts will open new options for understanding pathogenesis of individual EBV-linked diseases and developing targeted diagnostic and therapeutic approaches.

Epstein-Barr virus and nasopharyngeal carcinoma

Since its discovery 50 years ago, Epstein-Barr virus (EBV) has been linked to the development of cancers originating from both lymphoid and epithelial cells. Approximately 95% of the world's population sustains an asymptomatic, life-long infection with EBV. The virus persists in the memory B-cell pool of normal healthy individuals, and any disruption of this interaction results in virus-associated B-cell tumors. The association of EBV with epithelial cell tumors, specifically nasopharyngeal carcinoma (NPC) and EBV-positive gastric carcinoma (EBV-GC), is less clear and is currently thought to be caused by the aberrant establishment of virus latency in epithelial cells that display premalignant genetic changes. Although the precise role of EBV in the carcinogenic process is currently poorly understood, the presence of the virus in all tumor cells provides opportunities for developing novel therapeutic and diagnostic approaches. The study of EBV and its role in carcinomas continues to provide insight into the carcinogenic process that is relevant to a broader understanding of tumor pathogenesis and to the development of targeted cancer therapies.

Cancer "causation" by infections--individual contributions and synergistic networks

The search for infectious agents playing a role in human carcinogenesis and their identification remain important issues. This could provide clues for a broader spectrum of cancers preventable by vaccination and accessible to specific therapeutic regimens. Yet, the various ways of interacting among different factors functioning synergistically and their different modes of affecting individual cells should bring to question the validity of the term "causation". It also should put a word of caution into all attempts to summarize criteria for "causality" of infectious agents in cancer development. At least in the opinion of these authors, we would be much better off avoiding these terms, replacing "causal factor" by "risk factor" and grading them according to their contribution to an individual's cancer risk.

Detection and quantification of EBV, HHV-6 and CMV DNA in the gastrointestinal tract of HIV-positive patients

Human herpes viruses (HHVs) have been frequently detected in the gastrointestinal (GI) tract and may contribute to the development of gastric cancer. In the present study, the detection rate and viral load of Epstein Barr virus (EBV), HHV-6 and Cytomegalovirus (CMV) were assessed in the GI tract of human immunodeficiency virus (HIV) positive patients and of uninfected patients. The analysis revealed a significantly higher detection rate of EBV and HHV-6 in HIV-infected individuals than in uninfected subjects (88.5 vs 63%; p = 0.03). Moreover, EBV DNA load was significantly higher in the stomach of HIV patients than in controls. These data suggest that the HIV infection status may increase the persistence of these viruses in the GI compartment. Intriguingly, CMV DNA was undetectable in all biopsy specimens analyzed.

Evidence of Epstein-Barr virus association with gastric cancer and non-atrophic gastritis

Different lines of evidence support an association between Epstein-Barr virus (EBV) and gastric cancer (GC). The main understood risk factor to develop GC is infection by Helicobacter pylori (H. pylori), which triggers a local inflammatory response critical for progression from gastritis to GC. The role of EBV in early inflammatory gastric lesions has been poorly studied. A recent study proposed a cutoff value of 2000 EBV particles to identify patients with increased chances of infection of the gastric epithelium, which may favor the inflammatory process. To better understand the role of EBV in cancer progression, we analyzed 75 samples of GC, 147 control samples of non-tumor gastric tissue derived from GC patients and 75 biopsies from patients with non-atrophic gastritis (NAG). A first-round PCR was used for EBV detection in tumor and non-tumor controls and a more sensitive nested PCR for gastritis samples; both PCRs had lower detection limits above the proposed cutoff value. With this strategy 10.67% of GC, 1.3% of non-tumor controls and 8% of gastritis samples were found positive. An EBER1 in situ hybridization showed EBV infection of epithelial cells in GC and in a third of NAG samples, while in the other NAGs infection was restricted to the mononuclear cell infiltrate. EBV-positive GCs were enriched in lace and cribriform patterns, while these rare patterns were not observed in EBV negative samples. Our results support a role for EBV in GC and early precursor lesions, either as directly oncogenic infecting epithelial cells or indirectly as an inflammatory trigger.

Somatostatin receptor 1, a novel EBV-associated CpG hypermethylated gene, contributes to the pathogenesis of EBV-associated gastric cancer

BACKGROUND

Somatostatin receptor 1 (SSTR1) was preferentially methylated in Epstein-Barr virus (EBV)-positive gastric cancer using promoter methylation array. We aimed to analyse the epigenetic alteration and biological function of SSTR1 in EBV-associated gastric cancer (EBVaGC).

METHODS

Promoter methylation was examined by combined bisulphite restriction analysis (COBRA) and pyrosequencing. The biological functions of SSTR1 were evaluated by loss- and gain-of-function assays.

RESULTS

Promoter hypermethylation of SSTR1 was detected in EBV-positive gastric cancer cell lines (AGS-EBV) with SSTR1 transcriptional silence, but not in EBV-negative gastric cancer cell lines with SSTR1 expression. Expression level of SSTR1 was restored in AGS-EBV by exposure to demethylating agent. Moreover, methylation level of SSTR1 was significantly higher in EBV-positive primary gastric cancers compared with EBV-negative gastric cancers (P=0.004). Knock-down of SSTR1 in gastric cancer cell lines (AGS and BGC823) increased cell proliferation and colony formation ability, and promoted G1 to S-phase transition, enhanced cell migration and invasive ability. In contrast, ectopic expression of SSTR1 in gastric cancer cell lines (MKN28 and MGC803) significantly suppressed cell growth in culture conditions and reduced tumour size in nude mice. The tumour suppressive effect of SSTR1 was associated with upregulation of cyclin-dependent kinase inhibitors (p16, p15, p27 and p21); downregulation of oncogenes (MYC and MDM2), key cell proliferation and pro-survival regulators (PI3KR1, AKT, BCL-XL and MET); and inhibition of the migration/invasion-related genes (integrins, MMP1 (matrix metallopeptidase 1), PLAUR (plasminogen activator urokinase receptor) and IL8 (interleukin 8)).

CONCLUSION

Somatostatin receptor 1 is a novel methylated gene driven by EBV infection in gastric cancer cells and acts as a potential tumour suppressor.

Spontaneous clearance of Helicobacter pylori after pylorus-preserving gastrectomy for gastric cancer

Residual mucosa in the gastric stump after pylorus-preserving gastrectomy (PPG) is considered a risk factor for the development of gastric stump carcinoma (GSC). Duodenogastric reflux (DGR) and Helicobacter pylori (H. pylori) infection are suspected to contribute to the development of GSC. The aim of this study was to investigate the prevalence of H. pylori in the residual stomach after PPG for gastric cancer and to assess factors associated with the presence of H. pylori. We investigated 72 patients who had undergone PPG at least 1 year prior to the study and were confirmed to be positive for H. pylori infection on presurgical endoscopic biopsy. The extent of DGR, the prevalence of H. pylori infection based on H. pylori stool antigen (HpSA) tests and the severity of gastritis were analyzed in these post-PPG patients. None of the patients had DGR, as shown by (99m)Tc-PMT. Of the 72 post-PPG patients, 33 (46%) were positive for HpSA. The prevalence of H. pylori infection was significantly lower after surgery than before surgery. The endoscopic severity of remnant gastritis, as well as histological inflammation and activity, were higher in H. pylori-positive patients than in H. pylori-negative patients. In conclusion, some patients who undergo PPG and are negative for DGR experience spontaneous clearance of H. pylori infection.

Epstein-Barr virus infection is common in inflamed gastrointestinal mucosa

BACKGROUND AND AIMS

Epstein-Barr virus (EBV) is present in the malignant epithelial cells of 10% of all gastric adenocarcinomas; however, localization of the virus in normal gastrointestinal mucosa is largely unexplored. In the present study, we measured EBV DNA and localized viral gene products in gastritis specimens (n = 89), normal gastric and colonic mucosa (n = 14), Crohn's disease (n = 9), and ulcerative colitis (n = 11) tissues.

METHODS

A battery of sensitive and specific quantitative polymerase chain reactions targeted six disparate regions of the EBV genome: BamH1 W, EBNA1, LMP1, LMP2, BZLF1, and EBER1. EBV infection was localized by EBV-encoded RNA (EBER) in situ hybridization and by immunohistochemical stains for viral latent proteins LMP1 and LMP2 and for viral lytic proteins BMRF1 and BZLF1. B lymphocytes were identified using CD20 immunostains.

RESULTS

EBV DNA was essentially undetectable in normal gastric mucosa but was present in 46% of gastritis lesions, 44% of normal colonic mucosa, 55% of Crohn's disease, and 64% of ulcerative colitis samples. Levels of EBV DNA exceeded what would be expected based on the numbers of B lymphocytes in inflamed tissues, suggesting that EBV is preferentially localized to inflammatory gastrointestinal lesions. Histochemical staining revealed EBER expression in lymphoid cells of some PCR-positive lesions. The viral lytic viral proteins, BMRF1 and BZLF1, were expressed in lymphoid cells of two ulcerative colitis tissues, both of which had relatively high viral loads by quantitative PCR.

CONCLUSION

EBV-infected lymphocytes are frequently present in inflamed gastric and colonic mucosa. Active viral replication in some lesions raises the possibility of virus-related perpetuation of gastrointestinal inflammation.

Epstein-Barr virus-associated gastric carcinoma in Brazil: comparison between in situ hybridization and polymerase chain reaction detection

Epstein-Barr virus (EBV) has been associated with 10% of gastric carcinomas. The aim of this study was to determine the frequency of EBV in gastric carcinomas in Brazil assessed by in situ hybridization (ISH) and PCR, which would contribute to the characterization of the clinical and pathological aspects of EBV-associated gastric carcinomas. One hundred and ninety-two gastric carcinoma cases were collected at hospitals in two Brazilian states. Seventy-three out of 151 cases were PCR(+), while 11/160 cases were ISH(+). Nine out of eleven ISH(+) cases displayed a diffuse staining pattern and 2 out of 11 a focal pattern. Both techniques showed that the EBV(+) cases were characterized by their association with males, older patients, lower gastric region, intestinal type, advanced stage and poorly to moderately differentiated tumors. The concordance between the two techniques was 55.8% (Cohen's kappa index = 0.034). Four cases were ISH(+)/PCR(-), while 49 cases were PCR(+)/ISH(-). Only two cases showed stained lymphocytes by ISH and one of them was PCR(-). The observed discrepancy between the two techniques could not be explained just by the elevated accuracy of PCR. ISH(+)/PCR(-) carcinomas may be encountered if EBV is not present in the whole tumor tissue or if there are polymorphisms in the sequences of the viral genome amplified. On the other hand, the high frequency of PCR(+) results associated with the absence of ISH staining in lymphocytes and/or tumors cells suggests that the virus may be present in tumor cells or other cell types without expressing EBER1, the target of the ISH technique.

Possible role of EBV in breast cancer and other unusually EBV-associated cancers

Epstein-Barr virus (EBV) a ubiquitous gamma herpesvirus persists for life, generally without health consequences. However, it is associated with several well-recognized malignancies, such as Burkitt's lymphoma and nasopharyngeal carcinoma. A growing list of malignancies has been proposed to be EBV-associated: most of which are consistently EBV-positive whereas others show inconsistent results. The possible contribution of EBV to the development and/or progression of different "non-classical" tumors is discussed in terms of putative "non-traditional'' infection in EBV-related tumors.

Epstein-Barr virus DNA load in tumour tissues correlates with poor differentiation status in non-muscle invasive urothelial carcinomas

OBJECTIVE

To detect the correlation between the clinical staging, grading and genomic Epstein-Barr virus (EBV) viral numbers in tumour tissues of urothelial carcinoma patients.

PATIENTS AND METHODS

From June 2004 to May 2008, 60 urothelial carcinoma patients (50 cases of bladder carcinoma and 10 of upper tract urothelial carcinoma (UTUC) were enrolled in the study. Eight patients who underwent transurethral resection of prostate for prostate hyperplasia and two patients receiving nephrectomy for non-function kidney were used as normal controls. The EBV viral copy numbers in genomic DNA were evaluated using a real-time PCR-based study. The BamHI W region of the Namalwa cell line was constructed to the plasmid clone and was used as standard curve for absolute quantitative PCR (Q-PCR).

RESULTS

Epstein-Barr virus DNA was detected in 56% (28/50) and 60% (6/10) of the bladder and UTUC patients, respectively. The EBV DNA could not be detected in the normal control group. By pooling the UTUC and bladder patients in stage Ta,T1, the high copy number in fixed genomic DNA amount (100 ng/20 µL) was correlated with the high grading in stage Ta,T1 urothelial carcinoma (P = 0.014). The overall grading was not statistically associated with EBV copy number (P = 0.25). Although the copy numbers between paired tumour and normal tissues were not statistically different (P= 0.169), there were more copies of EBV in the normal tissues adjacent to the tumours than in those free from urothelial carcinoma. There was no significant difference between recurrence of non-muscle invasive bladder cancer and the presence of EBV (P > 0.05).

CONCLUSIONS

Epstein-Barr virus DNA could be detected in the genome of the urothelial carcinoma specimens. The poor differentiation status was correlated with the high load of the EBV genome in non-muscle invasive urothelial carcinoma. However, recurrence-free survival was not greater in EBV-positive patients than in EBV-negative patients.

Clinicopathological and molecular characteristics of Epstein-Barr virus-associated gastric carcinoma: a meta-analysis

There is conflicting data regarding the clinicopathological significance of the risk factors associated with Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC). To address this controversy, we performed a meta-analysis for the clinicopathological and molecular characteristics of EBVaGC. The relevant published studies were reviewed according to the defined selection criteria. The effect sizes of the outcome parameters were estimated by an odds ratio or a weighted mean difference. This meta-analysis included 48 studies that encompassed a total of 9738 patients. The frequency of EBVaGC was 8.8%, and EBVaGC was significantly associated with ethnicity. It was more predominant in men and in younger individuals. Interestingly, EBVaGC was more prevalent in Caucasian and Hispanic patients than in Asian ones. EBVaGC developed most often in the cardia and body, and it generally showed the diffuse histological type. EBV was highly prevalent in the patients with lymphoepithelial carcinoma. EBVaGC was closely associated with remnant cancer and a CpG island methylator-high status, but not with Helicobacter pylori infection, a TP53 expression, and p53 mutation. In addition, EBVaGC was not significantly associated with the depth of invasion, lymph node metastasis, or the clinical stage. The clinicopathological and molecular characteristics of EBVaGC are quite different from those of conventional gastric adenocarcinoma. However, further study is needed to determine the effect of EBV on the survival of EBVaGC patients.

Epigenetic dysregulation of the host cell genome in Epstein-Barr virus-associated neoplasia

Epstein-Barr virus (EBV), a human herpesvirus, is associated with a wide variety of malignant tumors. The expression of the latent viral RNAs is under strict, host-cell dependent transcriptional control. This results in an almost complete transcriptional silencing of the EBV genome in memory B-cells. In tumor cells, germinal center B-cells and lymphoblastoid cells, distinct viral latency promoters are active. Epigenetic mechanisms contribute to this strict control. In EBV-infected cells, epigenetic mechanisms also alter the expression of cellular genes, including tumor suppressor genes. In Nasopharyngeal Carcinoma, the hypermethylation of certain cellular promoters is attributed to the upregulation of DNA methyltransferases by the viral oncoprotein LMP1 (latent membrane protein 1) via JNK/AP1-signaling. The role of other viral latency products in the epigenetic dysregulation of the cellular genome remains to be established. Analysis of epigenetic alterations in EBV-associated neoplasms may result in a better understanding of their pathogenesis and may facilitate the development of new therapies.

Characteristics of Epstein-Barr virus-associated gastric cancer: a study of 235 cases at a comprehensive cancer center in U.S.A

Background

Epstein-Barr virus (EBV) has been shown to be associated with gastric cancer. However, inconsistent findings have been reported regarding the distribution of EBV infected cells (in normal gastric epithelium vs. intestinal metaplastic cells vs. in neoplastic cells) and the characteristics of EBV-associated gastric cancer. Lymph node positive EBV-associated gastric cancer has not been systematically studied. The aims of this study were to evaluate EBV-associated gastric cancer, to assess the distribution of EBV infected cells including all positive lymph nodes, and to define the characteristics of EBV-associated gastric cancer.

Design

The study included primary gastric cancer patients who underwent surgical resection with no preoperative treatment at M.D. Anderson Cancer Center between 1987 and 2006. Formalin-fixed paraffin-embedded tissue from these resection specimens were assessed for EBV by in situ hybridization, the gold standard for EBV detection in tissue. EBV status was analyzed along with clinicopathologic parameters including age, gender, tumor type, lymph node status, and pathologic stage of the tumor.

Results

Among 235 patients, 12 had intranuclear expression of EBV. EBV staining was seen only in tumor cells and no detectable EBV was observed in normal gastric mucosa, intestinal metaplasia or stromal cells. Eight of 12 patients with EBV-associated gastric cancer had regional lymph node metastasis. Of note, metastatic tumor cells in all of the involved lymph nodes of these 8 cases contained EBV. The epidemiologic data showed 11 of the 12 patients with EBV-associated gastric cancer were men, ranging in age from 54 to 78 years (mean age, 60 years; median age, 62.1 years). The age distribution for non-EBV associated gastric cancer patients ranged from 21 to 93 years (mean age, 67 years; median age, 66.4 years).

Conclusion

Our study demonstrated that EBV is present exclusively in gastric cancer cells. The detection of EBV in tumor cells in all of the lymph nodes involved with metastatic gastric carcinoma suggests simultaneous replication of EBV and tumor cells. The predominantly male gender and relatively younger age observed for the EBV-infected gastric cancer cases suggest an association between this disease and other factors, such as life style.

High levels of Epstein-Barr virus DNA in latently infected gastric adenocarcinoma

Gastric adenocarcinoma is the second leading cause of cancer death worldwide. Epstein-Barr virus (EBV) is present in the malignant cells of approximately 10% of cases. It is unclear whether EBV is being missed in some gastric adenocarcinomas due to insensitive test methods or partial EBV genome loss. In this study, we screened 113 gastric adenocarcinomas from low- and high-incidence regions (United States and Central America) for the presence of EBV using a battery quantitative real-time PCR (Q-PCR) assays targeting disparate segments of the EBV genome (BamH1W, EBNA1, LMP1, LMP2, BZLF1, EBER1) and histochemical stains targeting EBV-encoded RNA (EBER), the latent proteins LMP1 and LMP2, and the lytic proteins BMRF1 and BZLF1. EBV DNA was detected by Q-PCR in 48/75 United States cancers (64%) and in 38/38 Central American cancers (100%), which was a significant difference. EBER was localized to malignant epithelial cells in 8/48 (17%) United States and 3/38 (8%) Central American cancers. Viral loads were considerably higher for EBER-positive vs EBER-negative cancers (mean 162 986 vs 62 EBV DNA copies per 100,000 cells). A viral load of 2000 copies per 100,000 cells is recommended as the threshold distinguishing EBER-positive from EBER-negative tumors. One infected cancer selectively failed to amplify the LMP2 gene because of a point mutation, whereas another cancer had an atypical pattern of Q-PCR positivity suggesting deletion of large segments of the EBV genome. Three different viral latency profiles were observed in the cancers based on constant expression of EBER and focal or variable expression of LMP1 or LMP2, without lytic protein expression. We conclude that EBV DNA levels generally reflect EBER status, and a panel of at least two Q-PCR assays is recommended for sensitive identification of infected cancers.

Laboratory assays for Epstein-Barr virus-related disease

Epstein-Barr virus (EBV) infects various cell types in a wide spectrum of benign and malignant diseases. Laboratory tests for EBV have improved and are increasingly used in diagnosis, prognosis, prediction, and prevention of diseases ranging from infectious mononucleosis to selected subtypes of lymphoma, sarcoma, and carcinoma. Indeed, the presence of EBV is among the most effective tumor markers supporting clinical management of cancer patients. In biopsies, localization of EBER transcripts by in situ hybridization remains the gold standard for identifying latent infection. Other RNA- and protein-based assays detect lytic viral replication and can distinguish carcinoma-derived from lymphocyte-derived EBV in saliva or nasopharyngeal brushings. Analysis of blood using EBV viral load and serology reflects disease status and risk of progression. This review summarizes prior research in the context of basic virologic principles to provide a rational strategy for applying and interpreting EBV tests in various clinical settings. Such assays have been incorporated into standard clinical practice in selected settings such as diagnosis of primary infection and management of patients with immune dysfunction or nasopharyngeal carcinoma. As novel therapies are developed that target virus-infected cells or overcome the adverse effects of infection, laboratory testing becomes even more critical for determining when intervention is appropriate and the extent to which it has succeeded.

Epstein-Barr virus associated gastric carcinoma: epidemiological and clinicopathological features

In this paper, the roles of Epstein-Barr virus (EBV) in gastric carcinogenesis are discussed, reviewing mainly epidemiological and clinicopathological studies. About 10% of gastric carcinomas harbor clonal EBV. LMP1, an important EBV oncoprotein, is only rarely expressed in EBV-associated gastric carcinoma (EBV-GC) while EBV-encoded small RNA is expressed in almost every EBV-GC cell, suggesting its importance for developing and maintaining this carcinoma. In addition, the hypermethylation-driven suppressor gene downregulation, frequently observed in EBV-GC, appears to give a selective advantage for carcinoma cells. EBV reactivation is suspected to precede EBV-GC development since antibodies against EBV-related antigens, including EBV capsid antigen (VCA), are elevated in prediagnostic sera. Interestingly, the average anti-VCA immunoglobulin G antibody titer in EBV-GC patients was significantly higher among men than among women, whereas EBV-negative GC cases did not show such a sex difference. A higher frequency of human leucocyte antigen-DR11 in EBV-GCs suggests that major histocompatibility complex-restricted EBV nuclear antigen 1 epitope recognition may enhance EBV reactivation. EBV infection of gastric cells by lymphocytes with reactivated EBV is suspected to be the first step of EBV-GC development. Male predominance of EBV-GC suggests the involvement of lifestyles and occupational factors common among men. The predominance of EBV with XhoI+ and BamHI type i polymorphisms in EBV-GC in Latin America suggests a possibility of some EBV oncogene expressions being affected by EBV polymorphism. The lack of such predominance in Asian countries, however, indicates an interaction between EBV polymorphism and the host response. In conclusion, further studies are necessary to examine the interaction between EBV infection, its polymorphisms, environmental factors, and genetic backgrounds.

Association of Epstein-Barr virus antibody levels with precancerous gastric lesions in a high-risk cohort

We evaluated associations between Epstein-Barr virus (EBV) antibody levels and precancerous gastric lesions (chronic atrophic gastritis, intestinal metaplasia, and dysplasia) in 183 subjects from Linqu, China. Immunoglobulin G antibody titers to EBV nuclear antigen (EBNA) and viral capsid antigen (VCA) were determined by two-fold serial dilution using immunofluorescence assays. Histological progression and regression were assessed by gastroscopic examination at the time of phlebotomy and at follow up 2 years later. Antibody titers did not differ significantly among histological diagnoses determined at the time of phlebotomy. However, subjects with dysplasia at follow up had significantly higher geometric mean antibody titers for both anti-VCA and anti-EBNA. Subjects with greater than median antibody levels were more likely to progress between examinations, especially in the subgroup with intestinal metaplasia at the time of phlebotomy (odds ratios [95% confidence intervals]: 5.7 [1.6-20] for anti-EBNA >or=1:320; 3.8 [1.0-15] for anti-VCA >or=1:640). Our findings suggest a possible role for EBV reactivation at an early phase of gastric carcinogenesis.

Differential expression of apoptosis related proteins and nitric oxide synthases in Epstein Barr associated gastric carcinomas

AIM: To determine the incidence of Epstein Barr virus associated gastric carcinoma (GC) in Brazil and compare the expressions of apoptosis related proteins and nitric oxide synthases between EBV positive and negative gastric carcinoma.

METHODS: In situ hybridization of EBV-encoded small RNA-1 (EBER-1) and PCR was performed to identify the presence of EBV in GCs. Immunohistochemistry was used to identify expressions of bcl-2, bcl-xl, bak, bax, p53, NOS-1, NOS-2, and NOS-3 proteins in 25 EBV positive GCs and in 103 EBV negative GCS.

RESULTS: 12% of the cases of GC (25/208) showed EBER-1 and EBNA-1 expression. The cases were preferentially of diffuse type with intense lymphoid infiltrate in the stroma. EBV associated GCs showed higher expression of bcl-2 protein and lower expression of bak protein than in EBV negative GCs. Indeed, expressions of NOS-1 and NOS-3 were frequently observed in EBV associated GCs.

CONCLUSION: Our data suggest that EBV infection may protect tumor cells from apoptosis, giving them the capacity for permanent cell cycling and proliferation. In addition, EBV positive GCs show high expression of constitutive NOS that could influence tumor progression and aggressiveness.

Down-expression of tumor protein p53-induced nuclear protein 1 in human gastric cancer

AIM: Overexpression of tumor protein p53-induced nuclear protein 1 (TP53INP1) induces G₁ cell cycle arrest and increases p53-mediated apoptosis. To clarify the clinical importance of TP53INP1, we analyzed TP53INP1 and p53 expression in gastric cancer.

METHODS: TP53INP1 and p53 expression were examined using immunohistochemistry in 142 cases of gastric cancer. The apoptosis of gastric cancer cells was analyzed using the TUNEL method. The relationship between the expression of TP53INP1 and clinicopathological factors was statistically analyzed.

RESULTS: TP53INP1 was expressed in 98% (139/142 cases) of non-cancerous gastric tissues and was down-expressed in 64% (91/142 cases) of gastric cancer lesions from the same patients. TP53INP1 expression was significantly decreased (43.9%) in poorly differentiated adenocarcinoma compared with well or moderately differentiated adenocarcinoma (81.6%). Cancers invading the submucosa or deeper showed lower positively (59.1%) compared with mucosal cancers (85.2%). Decrease or loss of TP53INP1 expression was significantly correlated with lymphatic invasion (54.3% vs 82.0% without lymphatic invasion) and node-positive patients (31.3% vs 68.3% in node-negative patients). P53 was expressed in 68 (47.9%) patients of gastric cancer, whereas it was absent in normal gastric tissues. A significant association was also observed between TP53INP1 status and the level of apoptosis in tumor cells: the apoptotic index in TP53INP1-positive tissues was significantly higher than that in TP53INP1-negative portions. Finally, when survival data were analyzed, loss of TP53INP1 expression had a significant effect in predicting a poor prognosis (P = 0.0006).

CONCLUSION: TP53INP1-positive rate decreases with the progression of gastric cancer. TP53INP1 protein negativity is significantly associated with aggressive pathological phenotypes of gastric cancer. TP53INP1 is related to the apoptosis of gastric cancer cells. The decreased expression of the TP53INP1 protein may reflect the malignant grade of gastric cancer and is regarded as an adverse prognostic factor.

Morphological Evidence of an Activated Cytotoxic T-Cell Infiltrate in EBV-Positive Gastric Carcinoma Preventing Lymph Node Metastases

Recently, we showed that Epstein-Barr virus (EBV)-positive gastric carcinoma (GC) forms a distinct clinicopathologic entity with a better prognosis due to lower incidence of lymph node metastases (LN+). Here we investigated whether in EBV-positive GC more pronounced activation of cellular immune responses is associated with absence of (micro)metastases. Twenty EBV-positive primary tumors (PT) (9 LN+) were matched with 28 EBV-negative GC (11 LN+) for T- and N-stage, gender, and age. The PT (n = 28) and its LNs were analyzed by EBER RNA in situ hybridization and by immunohistochemistry for MHC class I and II expression, for CD3, CD8, CD4, CD20, CD56, CD83, and Granzyme B (GzB) expression. In LN metastases of EBV-positive GC, the EBV genome is maintained, excluding tumor escape by virus deletion. All GC express MHC class I independently of EBV status. In comparison with EBV-negative GC, EBV-positive GC have higher expression of MHC class II on the tumor cells (P = 0.029) and a more extensive infiltrate (P < 0.0001) of activated GzB+ CD8+ T cells (P = 0.028), which is most abundant in those EBV-positive tumors that do not metastasize (P < 0.0001). In addition, in EBV-positive GC without metastases, the infiltrate contains higher numbers of mature dendritic cells (DC) (P = 0.018). At present, the antigenic target has to be determined. These data support the notion that local triggering of cellular immune responses in EBV-positive GC prevents lymph node metastasis formation.